Reactor Feed Mixer

The first step in the analysis is to determine if zero degrees of freedom exist in any process unit. In this case, the analysis will be simplified because of the reduction in the number of equations requiring simultaneous solution. After analyzing each process unit, we then combine the equations to determine if the process contains zero degrees of freedom. When analyzing each unit separately, we will repeat some variables and equations. For example, in line 3, the composition and flow rate variables, and the mole fraction summation, are the same for the mixer exit stream and the reactor feed stream. Later, when we combine the various processing units to determine the process degrees of freedom, we will take the duplication of variables and equations into account. 

Reactor Furnace Heat Exchanger Feed Mixer Quench Separator Compressor Recycle Column Stabilizer Column Product Column Entire flowsheet ... 

As a further disadvantage, it is known concerning operation in many parallel micro channels that mixed flow patterns and even drying of the channels can occur [9, 10]. This comes from phase maldistribution to the channels. To overcome this problem, first solutions for phase equipartition have been proposed recently, but so far have not been applied for the mixers described here, but instead for mini-packed reactors, having feed sections similar to the mixers [11,12]. Nevertheless, numbering-up of dispersive-acting micro devices generally seems to be more complicated than for two-phase contactors (see Section 5.1.1). 

The feed-stream is pressurized to the operation pressure by a metering pump, and the air which is used as oxidant in the oxidation reaction, is compressed to the operational pressure in a four-stage compressor. Both streams are mixed in a static mixer inside the reaction chamber as it is shown in Fig. 9.4-10. The reactor has been described in the section 9.4.4.I. A more etal ed description of the pilot plant can be found in reference [7]. 

Remark 2 Note that at the inlet of each unit (i.e., CSTR, PFR, CSTR approximating PFR) there is a mixer while at the outlet of each unit there is a splitter. There is also a splitter of the feed and a final mixer. As a result, in addition to the unknown flow rates of each stream of the superstructure we have also as unknowns the compositions of outlets of each unit. Finally, the volumes of each reactor unit are treated as unknown variables. 

Fig. 1. ASPEN-Plus PFD of carbonic acid pretreatment process as analyzed in this study. Bl, pretreatment reactor (Rstoic) B2, screw mixer B3, blowdown tank and screw conveyor B4, slurrying tank and tank agitator B5, cooler B6, reflux drum and condenser B7, feed pump B8, in-line C02 mixer B9, heater BIO, pneumapress filter Bll, heat exchanger B12, loading pump B13, C02 compressor B14, primary filtrate pump.

The inlet pipes of the two starting reactants to the batch vessel were simply connected to the StarLam mixer [67]. The only difference to the previous feed lines was the installation of filter cartridges before the entries to the microstructured mixer, necessary to avoid blocking of the reactor. The pressure drop in the lines was lower than 3 bar so that it was possible to keep the pumps used before in the plant. At the outlet of the reactor, a tube reactor was installed. During optimization it was found that it is sufficient to insulate this tube to reach the temperature needed to finish the reaction. The pipe ended directly in the batch vessel where the second endothermic reaction step was carried out as before. 

A loop reactor is used for the bioconversion of methane to produce biomass used, e.g., as fish meal. This is a large-diameter pipe operated at high liquid circulation velocity with the 02/CH4 feed injected at several locations along the reactor. Cooling of the exothermic aerobic fermentation is accomplished by external heat exchangers. Static mixers are used to maintain gas dispersion in the liquid. 

In another US patent, [47], polyolefins and tires scrapes mixture is fed to the batch reactor equipped with a special mixer. A screw extruder or other device is used for feed... 

It seems that fluid-bed cracking reactor (thermal or catalytic) is the best solution for industrial scale. However, regeneration and circulation of so-called equilibrium cracking catalyst is possible for relatively pure feeds, for instance crude oil derived from vacuum gas oils. Municipal waste plastics contain different mineral impurities, trace of products and additives that can quickly deactivate the catalyst. In many cases regeneration of catalyst can be impossible. Therefore in waste plastics cracking cheap, disposable catalysts should be preferably applied. Expensive and sophisticated zeolite and other molecular sieves or noble-metal-based catalysts will find presumably limited application in this kind of process. The other solution is thermal process, with inert fluidization agent and a coke removal section or multi-tube reactor with internal mixers for smaller plants. 

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